Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Scsoul on November 14, 2013, 08:18:02 pm

Title: 11bm8 tubes
Post by: Scsoul on November 14, 2013, 08:18:02 pm

 I picked up some 11bm8 tubes cheap, these need 11v for the heaters,  I'm wondering  if there a way to use power transformer with more common 6.3, and 5 volt taps to supply the heater?  I was thinking of building one of the excellent 6bm8 amps i've seen on this forum, I do have a few antek transformers with 12v taps i could use but they would only make about 190v HV not sure how the bm8 would sound with that low plate voltage?

Title: Re: 11bm8 tubes
Post by: PRR on November 15, 2013, 12:25:07 am

> would sound with that low plate voltage?

Datasheet shows numbers from 100V to 200V. Are you looking for something else?

Design MAXimum voltage is 250V.

Yes, 6.3V+5.0V is very close to the 10.7V the tube is made for. But how you gonna power the other tubes? (Hint: it can be done.)

Title: Re: 11bm8 tubes
Post by: DummyLoad on November 15, 2013, 01:35:58 am

would something as shown in the attached pdf work?

respectfully,

--pete

Title: Re: 11bm8 tubes
Post by: Scsoul on November 15, 2013, 05:40:38 pm

Don't tease me PRR, i've tried google search not a whole lot of info on the 11bm6 out there and my go to oldtimer that ran a stand at the fleamarket has sadly passed on,  Dummyload i can't open that pdf
 If 200v is enough i could run a quad, I have a PT meant for a voltage doubler and 7868 tubes from a conn organ chassis using no doubler just diodes :help:

Title: Re: 11bm8 tubes
Post by: Scsoul on November 15, 2013, 09:59:45 pm

  PRR just a wild guess but would it involve more than one CT for the heaters?